Shell Programming and Scripting

Hi,
I wanted to add a newline character after every 100 characters in a file using a awk or shell without reading each line of the file.

I want to run a command on the complete file.

This does based on a string but i want to add a new line after every 100 characters ir-respective of the content.

perl -pi -e 's@AUSTRALIA@AUSTRALIA\n@g' testfile > newfile

Thanks

perl -pi -e 's/(.{1,100})/$1\n/g' testfile > newfile

'man fold'

Thank you... fold works good.....